Mode-Locked Laser Array Monolithically Integrated With MMI Combiner, SOA, and EA Modulator

The monolithic integration of four 10-GHz 1.55- μm AlGaInAs/InP mode-locked surface-etched distributed Bragg reflector lasers with a 4 × 1 multimode-interference optical combiner, a curved semiconductor optical amplifier, and electroabsorption modulator using relatively simple technologies-surface-etched distributed Bragg reflector and quantum-well intermixing-has been demonstrated. Our techniques have the advantage of eliminating crystal regrowth and antireflection coating processes that are required in traditional methods. The four channels can operate separately or simultaneously. They also can be synchronized at the same pulse repetition frequency by the injection mode-locked technique.